> > You can then pass it to the parameter input port of this pipeline:
>
> Singular? I.e. there is only one parameter input port?
> Implies I can't have multiple 'imported' variable definitions?
My example pipeline had only one parameter input port, but you can have as many you want in your pipelines.
> > Â <!-- "result" is not primary on p:parameters -->
> > Â <p:identity>
> > Â Â <p:input port="source">
> > Â Â Â <p:pipe step="parameters" port="result"/>
> > Â Â </p:input>
> > Â </p:identity>
> > </p:declare-step>
>
> Guessing, this is simply copying the param-set to the output port?
Right, the "result" port of p:parametrs is non-primary, so you have to connect to it explicitly if you want to do something with the result document.
> Next question, how do I refer to the values set in
> the external file? Is there some syntax for this?
>
> E.g. I want to run an XSLT transform using
> parameter $xslt_stylesheet as the stylesheet for the transform.
I think you have to use p:parameters to read the parameters document first. Then you can apply XPath expressions to the generated c:param-set document and use the results in, for instance, XProc variables or options, or in choose/when statements.
Regards,
Vojtech